Having worked at McDs and have extensive experience dealing with one of those machines, that’s not quite the case.
The machine has to do a pasteurisation cycle daily and it’s always run at the end of the night shift, or for a 24/7 store, at the crack of dawn when they are switching to breakfast. If you don’t, it locks out. This is usually on a timer and you can’t ignore it, the machines pretty clear when it wants you to put it into its pasteurisation cycle.
The pasteurisation cycle only takes a few hours so if it does error out, you can usually get it going again before breakfast ends.
It needs a full strip down once per week where you’d fully sterilise and clean all the parts and tanks.
Older non-computerised heat treat machines needed a full strip down daily, I doubt there are any of these left in operation mind.
The issue is the machines are utter garbage and very unreliable. They’d regularly throw cryptic error codes and unless you are super experienced with one of them or a authorised technician, you’ll have zero idea what any of it means.
The machines are full of hundreds of tiny parts and o-rings which are prone to getting lost or broken during the strip down process.
Someone’s your right, it is just an error with the cleaning or strip down process and doing it again fixes it. Other times not so much and if it throws a code, it locks out until it’s cleared.
The maintenance and repair is locked down do you can only use their authorised techs which cost £££ and the parts cost £££. We keep spares of all the small/moving parts which are touched in the strip down process but they often develop a lot of electronic faults which we couldn’t do anything with.
Even just stupid stuff like these things are in a hot kitchen, in the summer they sell a lot of milkshake and the machines working hard, the compressor overheats and shuts down.
The older manual non-computerised machines were much easier to deal with and generally more reliable - we used to have racks of parts for those ready to go if needed.
Trust me, the last thing a franchise owner wants if for this machine to be out of action, they are literally money printing machines when they are operating correctly.